The main reason there will be no charges, apparently, is that the accuser reportedly could not identify the players who allegedly raped her. Sanders writes:

At about 2:30 a.m. Oct. 23, RiverPlace employees saw Brown, Williams, Brewer and Milsap enter the hotel lobby with the woman. The players appeared to have to convince the woman to go farther, Rees wrote, but after a little time they all got in an elevator and went up to the fourth floor together.

About 40 minutes later, according to Rees’ memo, the woman emerged – alone and naked – from an elevator. She collapsed to the floor.

“They raped me,” she said.

("Rees" is Multnomah County Senior Deputy District Attorney Donald Rees.)

Hotel workers called the police. A noteworthy element: all the players apparently talked to the police, and all reportedly told the same story:

In the meantime, police separated the players, who the memo described as cooperative and giving consistent versions of events.

Brown told police he had eight drinks at the strip club and went back to his room to play video games after returning to the hotel.

Williams said he was initially in the room with the woman, Brewer and Milsap, but left not long afterward.

“Williams stated he observed [the woman] becoming upset and crying, stating she had been raped three times before and did not want to be raped again,” according to the memo. “Williams said [she] was crying even though no one had touched her.”

Brewer said the woman got naked and flopped on his bed. He built a divider with blankets and pillows, telling her she could sleep on the bed or the floor if she wanted to stay.

“Brewer stated he decided not to have sexual intercourse with [her] because she was too drunk and acting strangely,” according to the memo.

The players agreed among them that no one would have sex with her, according to the memo, in part because of her saying she had been raped in the past.

It's worth reading the whole story. There's plenty more. For instance, the memo cites a cab driver who remembered the accuser saying, on the way from the strip club to the hotel with the players, that she wanted to have sex with two of them. Brewer reportedly had the cab stop at a convenience store for condoms.